My bad, thought it would be easier to read, as you wouldn't have to download the zip to access the logs. Post hidden.
Yeah, it's an add-on. Kinda. I'm running UnRAID on a NUC, so no PCI slots. The NIC I'm trying to add is a usb to ethernet adapter. The 2 intel NICs reported are the onboard LAN and WiFi.
For troubleshooting purposes, I tried a different USB port (tried them all), no luck though. I also tested another USB NIC with the RTL8153 chipset, which works fine. Finally, tested Debian on the system I'm troubleshooting with the RTL8156 NIC, to be sure the adapter isn't faulty. It shows up (thankfully) within Debian.
If the NIC doesn't show up in the syslog, could it be the case of a missing driver? Should it even pop up if there's no driver present to support it?
For what it's worth, here's the adapter I'm trying to get working:
https://www.club-3d.com/en/detail/2467/usb_3.1_gen1_type_a_to_rj45_2.5gbps/